Expandable graphite and method

• US 6,149,972 A
• Filed: 01/29/1998
• Issued: 11/21/2000
• Est. Priority Date: 01/29/1998
• Status: Expired due to Term

• Current Assignee: NeoGraf Solutions, LLC
• Original Assignee: UCAR Graph-Tech Incorporated
• Inventors: Greinke, Ronald Alfred
• Primary Examiner(s): Meeks, Timothy
• Assistant Examiner(s): MICHENER, JENNIFER KOLB
• Application Number:
  US09/015,590
• Time in Patent Office: 1,027 Days
• Field of Search: 427/333, 427/215, 427/212, 427/220, 427/301, 427/399
• US Class Current: 427/220
• CPC Class Codes: C01B 32/225 Expansion; Exfoliation
• CPC Class Codes: C09K 2200/0208 Carbon
• CPC Class Codes: C09K 3/10 Materials in mouldable or extrudable form for sealing or packing joints or covers filling pastes C09D5/34

Abstract

Intercalated graphite flake which has enhanced exfoliation volume characteristics at relatively low exfoliation temperatures e.g. 600° C. is made by heating a blend of intercalated particles and an organic reducing agent in the temperature range of 25° to 110° C.

Claims

1. Method for providing intercalated graphite flake with increased exfoliation volume at exfoliation temperatures as low as 600°

C. which comprises;

(i) treating of graphite flake with an oxidizing intercalant solution to provide intercalated graphite flake having a surface film of oxidizing intercalant solution;

(ii) blending said intercalated graphite flake which has a surface coating film of the oxidizing intercalant solution with an organic agent reactive with the oxidizing intercalant solution at temperatures of from 25°

C. to 110°

C., selected from sugars, alcohols, aldehydes and esters in an amount of from 0.75 to 4% by weight of the graphite flake; and

(iii) heating the blend of step (ii) to a temperature in the range of 25°

C. to 110°

C. to promote reaction of the organic agent with the coating of oxidizing intercalant solution.

2. Method in accordance with claim 1 wherein a temperature in the range of 25°

C. to 110°

C. is maintained for at least one-half hour.

3. Method in accordance with claim 1 wherein said oxidizing intercalant solution is a mixture of nitric acid and sulfluric acid.

4. Method in accordance with claim 1 wherein said organic agent is decanol.

5. Method in accordance with claim 1 wherein said organic agent is hexadecanol.

6. Method in accordance with claim 1 wherein said organic agent is 1-octanol.

7. Method in accordance with claim 1 wherein said organic agent is 1-propanol.

8. Method in accordance with claim 1 wherein said organic agent is 1,3 propanediol.

9. Method in accordance with claim 1 wherein said organic agent is 1, 10 decanediol.

10. Method in accordance with claim 1 wherein said organic agent is decylaldehyde.

11. Method in accordance with claim 1 wherein said organic agent is ethylene glycol.

12. Method in accordance with claim 1 wherein said organic agent is monostearate.

13. Method in accordance with claim 1 wherein said organic agent is sucrose.